Prevalence of anemia and related deficiencies 10 years after gastric bypass--a retrospective study

Bariatric surgery has gained wide acceptance as treatment for severe obesity and is associated with decreased overall mortality. The aims of this study were to evaluate the prevalence of anemia long term after Roux-en-Y gastric bypass (RYGB) and to search for factors predicting anemia.

All 745 patients who underwent RYGB between 1993 and 2003 at either Örebro or Uppsala University Hospital and who were living in Sweden were invited to participate by providing a fasting blood sample and completing a questionnaire about their health status. Full blood count, serum iron, transferrin, vitamin B12, and folic acid were determined.

Follow-up was completed in 431 patients (58 %) with mean age 51.3 ± 10 years. Of all patients, 27 % had anemia postoperatively and related deficiencies; iron, folic acid, and vitamin B12 were seen in 20, 12, and 2 %, respectively. There was no correlation between anemia and sex, follow-up time, 25-OH vitamin D level, and preoperative or postoperative BMI. An inverse correlation was found between anemia and regular medical checkups concerning gastric bypass surgery.

Twenty-seven percent of patients had anemia more than 10 years after RYGB. Anemia does not seem to progress with time and was less common in patients with regular medical checkups. Thus, improved long-term follow-up is needed.